Electric switch



June 2, 1942. L. A. KEMPTQN 2,285,210

ELECTRIC SWITCH Filed sept. 28, 1940 2 sheets-sheet 1 111 vehtor: LeslieA. Kem pboh,

H is Attorhefg.

Jun? 2, 1942. L. A. KEMPToN l ELECTRIC SWITCH Filed sept. 2s, 1940 2Sheets-Sheet 2 ...u m -t n vnl r. ...om .w m3.. e. A VA 5 ...11n .l E WHL if Figsll.

Patented June 2, 1942 ELECTRIC SWITCH Leslie A. Kempton, Chicago, Ill.,assignor to Edison General Electric Appliance Company, Inc., Chicago,Ill., a corporation of New York Application September 28, 1940, SerialNo. 358,860

(Cl. ZOO-6) 5 Claims.

This invention relates to electric switches and more particularly tomultiple-position electric switches and has for its object the provisionof an improved device of this character which can be manufactured at lowcost.

In multiple-position electric switches it is customary to providespecial contact means formed of material capable of resisting pitting bythe arcs formed upon the making or breaking of the circuit beingcontrolled. In many instances the contact means is in the form ofcontact buttons made of silver which is known to have the desirable arcresisting properties. Such special contact means, and especially thosein the form of precious metal contact buttons, usually represent a largeproportion of the cost of a particular switch and this is especiallytrue in multiple-position switches which are used for domestic cookingappliances. Thus if the number of such special contact means requiredfor a particular multiposition switch could be reduced a substantialsaving in the cost of the switch could be made.

It is the specic object of this invention to provide a new and improvedmultiple-position switch in which the number of special arc resistingcontacts used may be substantially reduced without affecting the numberof control positions of the switch. Expressed differently, it is thespecific object of this invention to provide a multiple-position controlswitch with a reduced number of special arcing contacts and with meansfor controlling the sequence of operation of the contacts so that whenthe switch is moved to its different circuit controlling positions thevarious circuits will be made or broken at the arcing contacts provided.

While not limited thereto, this invention is particularly applicable tomultiple-position switches of the type described and claimed in UnitedStates Patent 2,203,236, issued June 4, 1940, on an application filed byCharles P. Randolph and me and assigned to the assignee of the presentinvention. While such multiple-position switches have many uses, theyare particularly applicable for controlling electric range heatingcircuits as described in the aforementioned patent. In accordance withthis invention there is provided in a switch of this type a plurality ofarcing contacts made of suitable arc resisting material such as silver,and a plurality of non-arcing or circuit changing contacts made of asuitable base metal capable of carrying the load current. Ineluded withthis contact construction is new and improved means for controlling thesequence of operation of the contacts so that the load circuits arealways made or broken at the arcing contacts as will more fully appearhereinafter.

For a more complete understanding of this invention reference should behad to the accompanying drawings in which Fig. 1 is a front elevation ofan electric switch embodying my invention; Fig. 2 is a rear elevation ofthe switch shown in Fig. 1 with a part removed so as to illustratecertain details of the construction; Fig. 3 is a sectional view taken onthe line 3--3 of Fig. 2 and looking in the direction of the arrows, theswitch of Fig. 3 being shown mounted on a supporting panel; Fig. 4 is apartial sectional View taken on the line 4--4 of Fig. 2 looking in thedirection of the arrows, showing details vof the contact structure ofthis invention; Fig. 5 is a view taken on the line 5--5 of Fig. 3looking in the direction of the arrows, parts being removed to showdetails of the cam construction; Figs. 6 and 7 are developed sectionalviews taken on the lines 6-6 and l-l respectively of Fig. 5, looking inthe direction of the arrows and showing details of related portions ofthe cam construction; Fig. 8 is a View similar to Fig. 4 showing amodified form of contact structure; Fig. 9 is a perspective view showingadditional details of the modied form of contact structure shown in Fig.8; Figs. 10-15, inclusive, are diagrammatic representations of theswitch shown in Figs. 1-7 showing the switch controlling a heatingelement having two resistances to provide various degrees of heat; and

Figs. 16-21, inclusive, are sectional views taken on the lines IS-IBthrough 2I-2I of Figs. 10-15 respectively showing the position of thecontact members in each position of the cam member illustrated in Figs.10-15.

Referring to the drawings, my invention has been shown in one form asapplied to a multipole switch intended to `control the heating circuitof a surface unit of an electric range. As illustrated in Figs. l-3,this switch comprises a supporting panel I0 formed of some suitableinsulating material such as a. phenol condensation product. Thissupporting panel is provided with a peripheral flange I I which definesa rectangular-shaped chamber I2. Mounted within the chamber at one endthereof, the lower end as viewed in Fig. 2, and secured to the panel bymeans of rivets is a series of line terminals I3, I4 and I5. Thehorizontal portions of these terminals extend along the lower end of thechamber I2 and are provided with pairs of contacts I6 and I1, I8 and I9,and 20 and 2I, re-

spectively, which will be described more fully hereinafter. The verticalportion of the line terminals I3--I5 projects beyond the lower wall ofthe chamber so that connections can be made exteriorly of the chamberwith a suitable source of supply (not shown). In .order to facilitatemaking electrical connections, the terminal members I3, I4 and I5 aresuitably bent so that the ends thereof lie in different planes, as shownin Fig. 3. Molded in the upper flange surface of the supporting panel isa plurality of openings 22 in each of which is provided a load terminalscrew 23 which is secured in position by means of a nut 24 and to whichis adapted to be lconnected the load being controlled.

Secured to the upper end of the chamber I2 by means of rivets 25 is aplurality of contact fingers 2li-SI, inclusive, which are made of asuitable resilient, electrically conducting material, such as phosphorbronze, and are interposed between the line terminals I3, I4 and I5 andthe load terminals 23 to control the transfer of power therebetween.Referring to Fig. 2, itV will be observed that the contact finger 28 isprovided with a portion 32 which projects through the top wall of thechamber 'and terminates under the extreme right terminal screw 23, asviewed in Fig. l, to form an .electrical connection between Vthe screwand the main portion of the contact The contact lingers 21 and 28, onthe e finger 25. other hand, are formed from a single strip of materialand the-fingers are in effectV legs of a substantiallyY U-shaped striphaving aV bridging -portion 33. Projectingoutwardly from the bridgingportion, in line with the contact finger 28 is a portion 34 which isfastened under the second terminal screw 23 Vfrom the right, as viewedin Fig. ,1,A to form an electrical connection between this loadterminal` and the contact fingers 21 and 28. The contact fingers 29 and3U are similarly formed froma single piece of substantially U-shapedmaterial which also is provided with a portion 35 which extendsoutwardly through the top'wall of the chamber and is fastened under thethird terminal screw from the right, as viewed in Fig. l, to form theelectrical connection betweenthe contact ngers V29 and 30 andtheterminal screw 23. The contact finger 3-Iv is similar to the linger 26and is provided with a portion 35 which extends outwardly through vthetop wall of the chamber and is fastenedunder the eXtreme left-handterminal 23 viewed iny Fig. l to form an lelectrical connection vtherewith. In order to maintain the various terminal lingers in theirrelatively spaced positions, a plurality of bosses 31 are molded in thebottom wall of the chamber I2 so as to lie between adjacent contactVngers.

In order to provide an electrical connection between the contact iinger3| and the pair of iingers 21 and v28; there is provided a U-shapedshunt strip 33 made of a suitable conducting material. `The legs of thisshunt strip are secured under the nuts 24 Vof the terminal members 23 sothat the shunt is 4spaced from the contact fingers and lies near the topof the chamber I2, as vshownV in Fig. 3. Moreover, as shown in Fig.

'3, the chamber I 2k is closed by a cover I2a formed by a plate ofAsuitable electrically insulating maf te-ri'al which is secured to thepanel I0 by means of 4rivets or sorneother suitable fastening means.

In order that the contact fingers may perform their circuit lcontrollingand v circuit changing functions 'eife'ctivelv each finger is providedwith a Acontact which cooperates with a corresponding contact providedon the line terminal members I3-I5. In the usual switch construction,both the line contacts and the contacts on the fingers are made ofa'suitable material capable-of withstanding the arcs which occur uponthe making or breaking of the load circuit. Contacts made Y sible toeffect a reduction in the number of these silver contacts requiredwithout affecting the life or reliability of the switch, the cost of aswitch can be materially reduced. y

In accordance with this invention, I have provided a new and improvedswitch construction by v which such a reduction in silver contacts canbe effected. Considered generally I have provided a multi-positionmulti-pole switch in which only a certain number of contacts are `madefrom arcresisting materials, `such' as silver and the like, and theseare termed arcing'contacts. l The remainder of the contacts are madeof,` a base material capable-of carrying the load current and are termednon-arcing contacts. of operation of these contacts is then controlledby a new and improved cam member so that 4the circuits being controlledare made andA ybroken at the arcing contacts whereas'the non-arcingcontacts serve merely ascircuit changing contacts. In other words, Ihave provided` inconjunction with my improved contact arrangement, newand improved means f'or controlling 'the sequence of operation of thecontactsso that upon the making of the various circuits controlled bythe multiposition switch, the arcing contacts, i. e., lthosema-de of amaterial capable of withstanding the arc generated, are closed after thenon-arcing or circuit vchanging contacts are closed, and, upon'thebreaking of the various circuits, the arcing contacts are Iopened beforeopening of the non-arcing contacts.

Turning now to the specific embodiment of my invention shown in thedrawings and referring to Fig. 4, itwill be observed thatl the-terminalmember I3 is provided with a pair of arc-resisting contact abutments,VIn the preferred form of this invention, these abutments, as well'asthe remainder of the arc-resisting abutments tobe described hereinafter,arefin the form of silver contact buttons. If desired, however, thesesilver contact buttons could be replaced by` a silver inlay or a heavysilverplatedirect Von the contact fingers or by suitable non-metallicarcresisting abutments such as `carbon ,Contact buttons. Arranged tocooperate with the silver contact buttons on the terminal'member I3 is apair of silver contact buttons V39 and 40 which are welded or otherwisesecuredtoV the contact fingers 2S and21, respectively. In additiontothese pairs of arcing' contacts, there is one other pair of arcingcontacts which arelikewise formed byV 'These'f'contactsalr thereforabe'`made from a base' material such asphosphor bronze and asA shown in Fig.4 they'are preferably formed by The sequencel pressing integral bossesI8, I9 and 2| in the line terminals I4 and |5 against which the end ofthe contact fingers 28, 29 and 3| are adapted to bear to form pairs ofcontacts |8-28, |9--29 and 2 |--3|, respectively. These pairs ofcontacts may be designated the non-arcing or circuit changing contactssince the only function they serve in the switch is to vary the circuitrelations of the circuits controlled by the switch. In order to protectthe non-arcing contact members from oxidation and corrosion during use,it has been found desirable to provide on these contacts a light silverflash or coating. However, it is to be understood that such a coating ismerely provided to increase the life of the switch as a whole and may beomitted without affecting the operation of the switch,

In order that the travel of the non-arcing contacts between their openedand closed positions may be the same as the travel of the arcingcontacts, the entire horizontal portion of the terminal member |4 andthe portion of the terminal member I5 in which is formed the non-arcingcontact 2| are offset as shown in Figs. 2 and 4 to bring the non-arcingcontacts provided in the terminal closer to the contact fingers 28, 29and 3|, In Figs. 8 and 9 I have shown a modied form of non-arcingcontact structure which may be employed. In this modified form it ispossible to arrange the horizontal portions of the terminal members |3,Ell and l5 in a line as shown in Fig. 8. This is made possible byforming in the end of the terminal members 28, 29 and 3| substantiallycylindrical bosses 42, 43 and 44 which cooperate, respectively, with thebosses |8, I9 and 2| provided in the terminal members |4 and I5.

As shown in Fig. 4, the contacts of the multiposition switch have anormally opened position and are moved to the closed position upon themovement of the contact iingers 26-3|. Provided in a series ofhorizontally aligned apertures in the panel lli is a series of pins45-5|l. These pins, when forced inwardly or to the right as shown inFig. 3, engage the ngers 26-3I, respectively, to move them outwardly ina direction to cause the contacts mounted thereon to engage therespective contacts on the line terminals I9|5. The movement of the pins45-50 is controlled by a cam 5| which preferably is in the form of aflat disk-like metallic member although this cam may be made from anyother suitable material.

In order to control the sequence of operation of the pins 45-50 so thatthe circuit connection between the line and load terminals of the switchwill be made at the arcing contacts after closing of the circuitchanging contacts and will be broken at the arcing contacts beforeopening of the circuit changing contacts, there is formed in the cam 5Ia series of arcuate depressions which lie in radial spaced relation sothat one depression or group of depressions is provided for controllingeach of the actuating pins in the switch. Referring to 5, it will beobserved that the pin 50 for actuating the contact finger 3| iscontrolled by the outermost arcuate depression 52 which is broken by asingle flat surface 53; that tuating the contact nger 2'| is controlledby the arcuate depression 66 which is separated by a single flat surface61; that the pin 48 for actuating the Contact finger 29 is controlled bythe arcuate depression 68 which is separated by the single elongatedflat surface E9; and that the pin 4l for actuating the contact nger 28is controlled by the arcuate depression 'l0 which is separated by asingle flat surface 1|, The length of the arcuate depressions and therelative position of the at surfaces which separate these depressions isdesigned so that, in operating the switch, at least one of the pins 45,46 and 49 for the contact fingers 25, 2l' and 30, respectively, will beactuated to close one pair of arcing contacts after the pins 4l, 48 and59 for the contact fingers 29 and 3l, respectively, have been actuatedto close the non-arcing contacts upon the making of a particular circuitand at least one of the pins 45, 46 and 49 will be actuated prior tomovement of any of the pins 41, 48 and 5|) to open the arcing contactsahead of the non-arcing contacts upon breaking of a particular circuit.In other words, the cam surface is so developed that the contact fingers26, 21 and 30 will be the last to be moved when a circuit is being madeand first to be moved when a circuit is being broken.

It is to be particularly noted as shown in Fig. 5 that the means foroperating the contact finger 25 comprises a series of arcuatedepressions which are separated by flat portions Whereas the means foroperating the remaining Contact fingers comprises a single arcuatedepression which is separated by a single flat portion. Thus it will beobserved that the contact nger 26 which is one of those provided withprecious metal contacts will be operated in every position of the switcheither to make or break the load circuit.

As has already been pointed out, the pins 45, 45 and 49 control thecontact fingers which operate the arcing contacts of the switch whereasthe pins 41, 48 and 56 control the contact fingers which operate thecircuit changing contacts for the switch. In order to insure that as theswitch is moved from one position to another the arcing contacts will beoperated in their proper sequence relative to the non-arcing contacts,the ilat surfaces of the cam over which the pin for operating thenon-arcing contacts must pass is made longer than the nat surfaces overwhich the pins for the arcing contacts must pass. The details of thisconstruction are clearly shown in the developed sectional views shown inFigs. 6 and 7 Referring to these views, it will be observed that thefiat surfaces 69 over which the pin for the non-arcing contact 29 passesbegins well in advance of the flat surface 59 over which the pin forarcing Contact 29 passes and terminates well beyond the end of the hatsurface 60 over which the pin for the arcing contact 26 passes. By thisconstruction it is positively assured that the non-arcing contacts willbe moved before the arcing contacts upon circuit making and after thearcing contacts upon circuit break. It will, of course, be understoodthat the relation shown in Figs. 6 and 7 obtains for the remainingarcing and non-arcing contact means.

As is clearly shown in Fig. 3, the cam 5| is rigidly secured to anoperating shaft 'F2 which is journaled at its inner end in a bearing 13provided for it in the panel lil and at its outer end in a bearing 'i4provided for it in a cupshaped cover member 'I5 which houses or enclosesthe cam. In order to secure the housing 15 to the panel I9, there isprovided on the edge of its side wall a pair of oppositely spacedfingers l'I6 which are secured to the panel by means of rivets 11.

In order to hold the cam 46 in anyparticular selected controllingposition, a positioning member 18 is provided which is secured to theshaft 12 by means of a splined connection (not shown) .f

positions are substantially 69 degrees apart.V

Mounted on opposite sides of the positioning cam is a pair of flatsprings 89 which at'their opposite ends are secured to opposite sides ofthe housing 15, as shown in Figs. 1-3. For this purpose the springs 89are provided at their ends with eXtensions 8l which are directed'through apertures provided for them in the housing. The upper and lowerends of the springs, as shown in Fig. l, are spaced sufliciently closetogether so that the central sections of the springs are pressed againstthe sides of the positioning member thereby to hold it resiliently inany controlling position to y which it is moved.

lWhen the switch is used to control the surface unit of an electricrange, it will normally be mounted on a panel 92 at the iront of therange so that the shaft '12 extends outwardly therefrom. Mounted on theprojecting end of this shaft is a knob 83 by which the switch may bereadily operated to its various circuit controlling positions. As shown,the knob may have a substantially triangular shape in order to provide avisible indication of the circuit controlling position of the switch. Inpractice, the casing of the switch is used for mounting the switch on apanel 82 and for this purpose it is provided with a pair of threadedapertures into which screws 84 are threaded as clearly shown in Fig. 3.

The switch of Figs. 1-'7 is diagrammatically shown in Figs. 10-15 ascontrolling the energization of a heating unit, such as the surface unitof an electric range, having two resist-ance ele-- m-ents 85 and 85which are energized from a suitable source of supply. As shown in Figs.

l0l5, the unit is connected through the switch to a three-wire supplysource 8?, 85 and 99 which provides two diiferent voltages which may beimpressed ony the heating unit. The wires 'i and 38 are outside wires ofthis source while the wire 89 is the neutral and the voltage between thetwo outside wires is substantiallyV twice the voltage between any oneoutside wire and the neutral. As shown, the outsideV er left-hand end ofthe resistance 85 is connected through a load terminal to conductingstrips lili and 13? and the outside end of the resistance is connectedthrough a load terminal to the strip 32. The opposite ends of the unitsg5 and :ES are connected together and the common connection is connectedthrough a load terminal to the conducting strip 35. The three lineterminals I"- 5 and their corresponding pairs of contacts are connectedas shown to the three wires iL-159 respectively.

In considering the operation of my improved multi-position'switchreference will be had to Figs. 10-15 which diagrammatically show eachcircuit controlling position of my improved multiposition switch and toFigs. 16-21 which are sectional views through the pin actuators showingthe position of the cover, pins and contacts of the switch for eachcircuit condition ydiagrammatically represented in Figs. 10-15respectively.

Referring first to Figs. 10 and 16, these views show the off position ofthe switch. be observed that the pins i5- 59 are each located in theirrespective depressions in the cam so that they are in their retractedposition. Thus all of the switch contacts are in their normally openposition and no energy is transferred from the line to the load. ItVwill be noted that in this position the heating elements 85'and 39 arecompletely isolated from the power 'supply conductors because of themulti-pole switching arrangement. This is a desirable feature and isoften required for safety purposes. p

Assuming now that the knob 83 is rotated clockwise from the positionshown in Fig. lV to the next succeeding indexed position, the cam 5iwill be rotated clockwise through approximately 6i) degrees to theposition shown in Fig, 1l. In this movement of the Vcam the pins 47, 49and 59 4for the contact fingers 28, 30 and 3l remain in their retractedposition. However, during the rst part of this movement, the pin t8 ofthe contactnger 29 moves out of its depression 68 and up onto the iiatsurfaceV 69 so that the nonarcing contacts l!) and 29 are closed. As themovement continues, the pin 65 for the contact finger 2 moves out'of itsdepression di and onto the flat surface `fi so that the arcing contactsl1 and are closed and the pin 45 for the linger 29 moves out of thedepression 513 and onto the flat surface 59 so that the arcing contactsI5 and 39 are closed. The position of the contacts in this position ofthe cam is shown in detail in Fig. 17. l/Vith the contacts in theposition illustrated itv will be apparent from Fig. 1l that the two vheating elements and 86 are placed in parallel across the outside wires8l and 88 so thata maximum heat output is obtained. This position of theswitch is termed the high heat or speed position.y

VAssume now that the switch is turned to its next indexed position whichcorresponds to a rotation of the knob 83 and the lcam 5l clockwisethrough an additional 6G degrees. In the first part of this movement theactuating pin for the Contact finger 25 moves off thefat surface 59 andinto the next succeeding depression causingV the arcing contacts I5 and39 to be opened, thus opening the circuit of the heating element S6. Asthis clockwise movement increases, the operating .pin 45 of the contactringerr remained on the flat surface 69 so that the nonarcing contactsi9 and 29 remain closed during the switching movement as is clearlyshown in Fig. 6. With the contacts I9 and 29, l5 and 39 closed as shownin Fig. 18, the heating element t8 alone is connected across the outsidewires 81 and 88 as is clearly shown in Fig'. l2 to produce the halfspeed position of the switch. Y

It Will f Assume now that the switch is advanced from the half speedposition to the next succeeding indexed position which corresponds tomoving the cam I through an additional 60 degrees. In this movement thefirst operation which takes place is that the pin 45 for the contactnger 26 moves off the fiat surface 6D and into the next succeedingdepression 56 to cause the circuit for the heating element 85 to beopened. After the pin 45 has moved into the depression -56 and as themovement further continues, the operating pin 48 for the contact finger29 moves off the fiat surface 69 and into the depression 68 to cause thenon-arcing contacts I9 and 29 to be opened and simultaneously theoperating pin 41 for the contact finger 28 moves out of the depression10 and onto the fiat surface 1I to cause the non- -arcing contacts I8and 28 to be closed. Upon the final movement of the cam to this thirdposition, the pin 45 for the contact finger 26 moves out of thedepression 56 and onto the fiat surface 6I to cause the arcing contactsI6 and 39 to be closed. With the contacts I8 and 42 and I6 and 39 closedas shown in Fig. 19, it will be observed from Fig. 13 that the heatingelements 85 and 86 are placed in series across the outside wires 81 and88 to produce a quarter heat position of the'switch.

Assume now that the switch is advanced from the quarter heat position t0the next succeeding indexed position which corresponds to a rotation ofthe knob 83 and the cam 5I through an additional 60 or through an angle240 degrees from the off position shown in Fig. 10. In the first part ofthis movement the pin 45 for the contact linger 26 moves off the fiatsurface 6I and into the. depression 51 to cause opening of the arcingcontacts I6 and 39 thereby opening the heating -circuit of the seriesconnected elements 85 and 86. As the movement continues, the pin 41 forthe contact finger 28 moves off the flat surface 1I and into thedepression 10 to cause opening of the non-arcing contacts I8 and 28. Asthe movement advances still further, the pin 49 for the contact finger30 moves out of the depression 64 and onto the flat surf-ace 65 to causeclosing of the arcing contacts 20 and 4I `and the pin 45 for the contactfinger 26 moves out of the depression 51 and onto the fiat surface 62 tocause closing of the arcing contacts I6 and 39. With the contacts I6 and39 and the contacts 20 `and 4I closed as shown in Fig. 20, it will beobserved from Fig. 14 that the heating element 86 is now connectedacross the outside wire 81 and the neutral wire 89 and is thus energizedat substantially half the voltage between the two outside wires so as toproduce the thrift heat position of the switch.

Assume now that the switch is advanced from the thrift position to itsnext succeeding indexed position which corresponds to rotation of theknob 83 and cams 5I through an additional angle of 60 degrees. In thefirst part of this advance the pin 45 for the contact finger 26 movesoff the fiat surface 62 and into the next succeeding depression 51 toopen the arcing contacts I6 and 39. As the movement continues, the pin49 for the cont-act finger 30 moves off the flattened portion 65 andinto the depression 64 to :cause opening of the arcing contacts 4I and20. Upon la still further advance, the pin 50 for the contact finger 3Imoves out of the depression 52 and into engagement with the fiattenedsurface 53 to cause closing of the non-arcing contacts 2I and 3I andsubsequently the pin 45 for the contact finger 26 moves out of thedepression 58 and onto the flat surface 63 to cause closing of thearcing contacts I6 and 39. With these pairs of contacts closed as shownin Fig. 21 it will be observed from Fig. 15 that the heating elements 85and 86 are connected in series across the outside wire 81 and theneutral wire 89 to produce the lowest heat output for the circuit whichis termed the Warm position of the switch.

By advancing the switch to the next indexed position the knob cam willhave been rotated through 360 degrees and hence will be in return theoff position shown in Fig- 10. In the first part of this movement to theoff position, the pin 45 for the contact finger 26 will move ofi theflattened surface 63 and into the depression 54 to cause opening of thecontacts I6 and 39. 'Then as the advancing movement continues, the pin'5D for the Contact finger 3| will move off the fiattened surface 53 andinto the depression 52 to cause opening of the non-arcing contacts 2|and 3|.

Through all of the above multi-pole switching and circuit changingoperations as the switch is moved through its six positions, it will beobserved that in every instance the non-arcing contacts are closedbefore the arcing contacts upon the making of a circuit and the arcingcontacts are opened before the non-arcing contacts upon the breaking ofa circuit. Thus any arcing which occurs upon the closing or opening ofthe circuit will take place at the silver arcing contacts and the basemetal non-arcing contacts serve merely as circuit changing contacts.

From the foregoing detailed description it will be observed that I haveprovided a new and improved multiple-positioned switch constructionwhich can be manufactured at low cost, the salient cost reduction beingproduced by so constructing and arranging the switch that the number ofprecious metal contacts used thereiny may be substantially reduced andin the case of a six-position switch may be reduced by half.

While I have shown and described a particular embodiment of myinvention, it will be understood. of course, that I do not intend to belimited thereto since many modifications can be made. I, therefore,contemplate by the appended claims to cover all such modifications asfall within the true spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the UnitedStates is:

l.. A multi-position multi-pole switch comp-rising an insulatingsupporting panel, a plurality of resilient contact fingers mounted onsaid panel. a plurality of pairs of relatively movable contactscomprising relatively fixed contacts mounted on said panel andrelatively movable contacts carried by said contact fingers, said pairsof contacts including at least one pair of arcing contacts and at leastone pair of nonarcing contacts, means comprising a rotary operating camhaving cam surfaces for actuating said fingers to close said pairs ofcontacts when said cam is rotated, said cam having at least one switchclosing position in which a plurality of pairs of said contactsincluding at least one pair of arcing contacts and one pair of nonarcingcontacts are closed to effect a multi-pole switching function, said camsurfaces being arranged so that upon movement of said cam to said switchclosing position the arcing contacts are closed subsequent to thenon-arcing contacts and upon movement of said cam from said switchclosing position said arcing contacts are opened prior to saidnon-arcing contacts whereby arcing occurs only at said arcing contacts.

`2. A multi-position multi-pole switch comprisingan insulatingsupporting panel, arplurality of normally open pairs of relativelymovable contacts mounted on said panel, said pairs of contactscomprising pairs of non-arcing contactsand a Vpair of arcing contacts,and means comprising a rotary cam having cam surfaces foreffecting aclosure of said pair of arcing contacts and different pairs of saidnon-arcing contacts when said cam is rotated to a plurality of switchclosing positions to effect a different multi-pole switching function`in each switch closing position, said cam surfaces being arranged sothat when said cam is rotated away from any one of said switch closingpositions said arcing contacts are opened prior to said non-arcingcontacts whereby arcing occurs only at said arcing contacts.

3. A multi-position )multi-pole switch comprising an insulatingsupporting panel, a plurality of pairs of relatively movable normallyopen contacts mounted on said panel, said pairs of contacts including atleast one pair of non-Y arcing contacts and at least one pair of arcingcontacts, means comprising a single movably mounted cam member forvclosing all of said pairs of contacts, said cam member having at,

1 closed subsequent to the non-arcing contacts and upon a movement ofsaid cam from said switch closing position said arcing contacts areopened prior to said non-arcing contacts whereby arcing occurs only atsaid arcing contacts and only said arcing contactsl need be formed ofarc resistant material.

4. A multi-position multi-pole switch comprising an insulatingsupporting panel, a plu` rality of pairs of relatively movable contactsmounted on said panel, said pairs of contacts including at least onepair of non-arcing contacts Vand at least one pair of arcing contacts, asingle movably mounted cam member for actuating all of said contacts,said cam member being movable to aV switch opening position in whichsaid pairs of contacts are open and to at least one switch closingposition in which a pair of non-arcingr and a pair Vof arcing contactsare closed to effect a multi-pole switching function, said cam memberbeing shaped so that upon a movement of Ysaid cam member to said` switchclosing position the arcing contacts are closed subsequent to thenon-arcing contacts whereby arcs formed upon the closing 0f saidcontacts are dissipated at said arcing contacts.

5. A multi-position multi-pole switch comprising an insulatingsupporting panel, a plurality of pairs of relatively movable contactsmounted on said panel, said pairs of contacts including at least onepair of nonarcing contacts and at least one pair of arcing contacts, asingle movably mounted cam member for actuating all cf said pairs ofcontacts, said cam Ymember being movable to a switch opening position inwhich said pairs of contacts are open and to at least one switch closingposition in which a pair of non-arcing and a pair of arcing contacts areclosed'to eiect a multi-pole switching function, and said cam memberbeing shaped so thatV upon a movement of said cam member from saidswitch closing position said arcing contacts are opened prior to saidnon-arcing contacts whereby arcs formed upon the opening of saidcontacts'are dissipated at said arcing contacts;

LESLIE' A. KENIPTON.

